Research in probiotics is an important and developing area across many aspects of health and wellbeing. Synthesizing the most contemporary evidence, this book examines the role of probiotics in the context of major mental health and clinical diagnoses. It addresses etiology and prognosis and explores the therapeutic potential of probiotics within each diagnostic category. Diagnostic categories include anxiety disorder, major depressive disorder, addiction, eating disorder, bipolar affective disorder, and schizophrenia. The text highlights future research directions and contains summary points for each chapter.